Process and device for casting components

ABSTRACT

The invention relates to a process and devices for casting components in metal alloys on the tilt casting principle in which a quantity of melt metered for casting is spread over a large gate cross section without turbulence from a melt container of the mould (30) into the mould (31) by rotating the casting device. To prevent the formation of oxide and weak structural points, the melt is taken from a metering furnace under a protective gas in a melt container connected to the mould and taken thence into the mould also under a protective gas. The melt hardens there under increased gas pressure on the feeder region of the casting, whereby its properties such as fine-grained, dense structure, high stability under load and accurately dimensioned surfaces are considerably improved.

BACKGROUND OF THE INVENTION

The invention relates to a process of and device for casting components,with liquid metal being introduced into a cavity of a mould where it isconsolidated. For forming components, starting from the liquid materialcondition, there is known a large number of different processes anddevices which more or less meet the requirements to be complied with byhigh-quality workpiece in respect of shaping freedom, surface qualityand especially optimum material properties. The main difficultiesinitially concern the operation of filling the mould wherein theinitially compact melt volume is divided, with a large surface thereofbeing exposed to air atmosphere, which, due to certain reactions, leadsto the material quality being adversely affected. Molten metal alloyswhose alloying constituents react very strongly to oxygen, nitrogen andthe water vapour of air are particularly affected. In consequence, thetilting casting method according to Durville for example was applied tosensitive alloys at an early stage.

DE-PS 377 683 proposes a process wherein numerous casings are producedone after the other from an oblong casting container. In the course ofthe casting operation, the melt container is erected, as a result ofwhich a somewhat higher metallostatic pressure can be achieved. However,with this method, the atmosphere has free access to the melt, so thatespecially as the container empties, oxide can easily reach the mouldcavity from the bath surface. During the solidification of the castingsthere remains a direct connection with the large melt volume in thecasting container, so that the solidification process is slowed down.

DE-PS 505 224 describes a process wherein two moulds alternately filledwith melt are mounted on a casting container arranged similarly to aswing. Again, the air has free access to the melt bath with its largesurface, so that it is particularly easy for the existing impurities toenter the mould.

DE-PS 21 64 755 describes a high-performance casting process for largeseries wherein, admittedly, the disadvantages of the above proposalswere largely eliminated, but it requires sophisticated, expensiveequipment, and even if one single mould fails, the remaining parts areaffected as well.

As a rule, during the solidification process, volume contractions andgas segregations cause the component structure to form shrinkholes andpores which have to be eliminated at great expense. The shrinkingprocesses also, locally, lead to the formation of gaps between thesurfaces of the casting wall and mould wall, which gaps greatly affectthe heat transfer, which also has negative effects on the quality of thestructure and leads to sink marks, thus rendering the component useless.

SUMMARY OF THE INVENTION

It is the object of the invention to use new types of processes andcasting facilities to create the advantageous conditions required forproducing high-quality components, both during the mould fillingoperation and also during solidification of the castings, and at thesame time to permit particularly rational production and eliminate thedisadvantages of the above-mentioned processes and devices. The purposeis to avoid turbulence and melt division during the mould fillingoperation. Furthermore, it is the object of the invention to prevent anyreactions of the alloy melt with the gases of the atmosphere and of themould cavity. Finally, the intention is, preferably, to achieve sharpcontours during the filling process and to ensure an optimumfine-grained and dense component structure during the solidificationprocess.

To achieve the objective there are proposed processes and a suitabledevice having the characteristics of the independent claims, with asealable container for the melt being connected by a large ingatecross-section to the cavity of the mould which, initially, is positionedabove the container.

The ingate constitutes the direct connection between the castingcontainer and the mould cavity and shall be dimensioned in such a way asto avoid the melt being throttled or subjected to turbulence. Accordingto a first proposal, its large cross-section relative to thecross-section of the gated mould cavity and the adjoining mould wallparts of the component may amount to a value in excess of 40%,especially in excess of 50%, of the latter cross-sectional faces.According to a second proposal, the large cross-section relative to thecross-section of the gated mould cavity and the cross-section of theadjoining mould wall parts may amount to a value in excess of 50%,especially in excess of 70% of the latter faces, and preferably extendalong their entire length. The ingate communicates with the lowest partsof the mould cavity or the mould wall part prior to the rotatingoperation. Only their cross-sectional faces extending parallel to thecross-section of the ingate are referred to as gated faces to which theingate is preferred during the relative dimensioning process.

The casting container is preferably first flushed with protective gas,then filled with a metered quantity of melt under protective gas andsealed so as to be gas-proof, whereupon the container together with themould is rotated around a horizontal axis in such a way that the melt isconveyed into the mould without forming any preceding tongues or spray.

In a preferred embodiment, the pressure of the protective gas isincreased during the mould filling operation end/or the solidificationprocess, and it is advantageous if the protective gas is recoveredduring the subsequent pressure relieving process.

All processes in accordance with the invention have in common that thecasting container is filled with an amount of melt which corresponds tothe gross volume of the quantity of melt for one component required forone casting operation and which solidifies in its entirety during thecasting operation, with only a small volume of melt forming the feedervolume remaining in the ingate itself or possibly in the castingcontainer.

According to a first process in accordance with the invention, to avoidany oxidation, even the casting container is filled with liquid meltunder protective gas, with the application of protective gas beingcontinued while the casting container is rotated together with themould.

According to an alternative process, a volume of solid metalcorresponding to the quantity of melt is introduced into the castingcontainer; only then will the casting container and mould be sealinglyconnected and the interior flushed with protective gas, whereupon thequantity of melt required for one casting operation is melted in thecasting container. Otherwise, the process remains unchanged. In thiscase, too, any oxidation processes during the liquid phase aresuccessfully avoided.

To improve the structure, the pressure of the protective gas isincreased during the solidification process, as a result of which thefeeder volume and thus the amount of metal used is reduced, as theexcess pressure on the melt surface in the casting container replacesthe otherwise common metallostatic pressure of high-level feeders.

According to a further process in accordance with the invention forimproving component quality, no protective gas is used in the case ofalloys less likely or less at risk to form oxidations, while otherwiseretaining the latter process sequence involving the increase in pressurein the inferior of the casting container during the mould fillingoperation and/or the solidification process in order to achieve the sameeffects of a reduced use of metal and an improved structure and surfacequality of the casting.

According to an alternative process it is possible to introduce thequantity of melt into the casting container either in liquid form or ina solid condition and then melt it in the casting container. Otherwisethe process remains unchanged as compared to the previous process.

According to a further process in accordance with the invention forimproving castings which, because of the alloys used and/or their shape,are less likely to form shrinkholes or sink marks, the process iscarried out without building up an excess pressure, but with a certainamount of melt remaining in the ingate and preferably in part of thecasting container after the rotating operation in order to generate ametallostatic pressure.

In this case, too, according to an alternative embodiment of theprocess, it is possible to introduce the quantity of melt into thecasting container either in liquid form or in a solid condition andsubsequently melt it in the casting container. Otherwise the processremains unchanged as compared to the above-mentioned process.

The processes in accordance with the invention, in particular, eliminatethe risk of impurities and inclusions in the casting in that, ascompared to the existing component surface and the gated part of themould cavity, there is provided a large ingate cross-section or that, ascompared to the size of the casting and the mould cavity, there isprovided a long ingate in the direction of the rotational axis. As aresult, the metal flow from the casting container into the mould isquiet and preferably located below the bath surface so that adefect-free casting is produced.

The ingate with the large cross-section is identical with the feedchannel and at the same time constitutes the feeder volume. It forms thedirect connection between the interior of the casting container and themould cavity.

Further embodiments are characterised by a number of considerableadvantages. When transferring a metered amount of melt from a motoringfurnace into the casting container of the device under protective gasatmosphere, melt oxidation is effectively avoided. This is all the moresignificant because, with this process, the molten metal stream reachesthe casting container under free fall conditions, and unlikeconventional operations, there is no large-scale formation of oxideskin, with the melt continuously breaking off, rushing in or whirling.Because of the predetermined large ingate cross-section, the mouldfilling operation starting as a result of the rotational movement of theequipment can then take place particularly quietly and at a low speed offlow of the melt in a rising mode according to the principle ofcommunicating tubes, which, especially in connection with a protectivegas atmosphere also prevailing in the mould cavity, effectivelyeliminates the risk of foam formation which of course leads toinclusions in the structure of the casting. The front end of the meltremains closed, i.e. the formation of preceding metal tongues or evenspray is avoided, thereby also preventing cold runs which are oftenfeared as the cause of rejects in casting operations.

According to a preferred embodiment, the mould cavity for an oblongcomponent is aligned in the direction of the rotational axis, therebyachieving a wide melt front end.

According to a further embodiment, cores are arranged so as to bepositioned towards the casting container. As a result, the gated mouldwall parts themselves are reduced to end wall parts of the component inorder to improve quality.

In the case of castings such as cylinder heads or cylinder crankhousings of internal combustion engines, any surfaces having to meetstringent quality requirements are to be arranged at a mould wallpositioned opposite the ingate.

Solidification is to be controlled by heating and/or cooling in such away that it progresses from the component point furthest removed fromthe casting container in the direction towards the ingate.

According to a preferred embodiment, there is provided a furtherover-flow channel so as to extend parallel to the ingate, so thatinitially the gas or air volumes may be balanced in order to avoid theformation of foam.

By closely connecting the casting container to the mould cavity it ispossible to achieve extremely short flow distances. The melt reaches itsfinal position over the shortest distance, cools rapidly and solidifies.As a result, it is possible to eliminate the "canalisation effect" whichoccurs in conventional mould filling operations as a result of metalfollowing or flowing through certain regions over long periods of time.

Said advantages also benefit the subsequent solidification process.First, the thermal conditions in the mould are disturbed to a muchlesser extent due to the elimination of the canalisation effects whichcause local overheating both in the casting and in the adjoining mouldwall regions, thus advantageously affecting control of thesolidification process.

Furthermore, an increased, especially variable protective gas pressureduring solidification provides special advantages. By greatly increasingthe gas pressure, which mainly affects the melt surface which is locatedat the upper end after completion of the mould filling operation andunder which there is positioned the feeder volume of the casting, it ispossible to increase the feeder pressure and achieve a largely densestructure of the casting. At the same time, the casting surfaces arefirmly pressed against the mould walls and by preventing the formationof damaging gaps, the transfer of heat is intensified.

The above, in turn, shortens the solidification time and increases boththe contour sharpness and dimensional accuracy of the castings. Inaddition, it is possible to eliminate the formation of sink marks at thecasting surface which are particularly likely to occur on alloysrequiring a long period of solidification. Because the process islimited to the relatively small volume of one single casting, the gaspressure may be increased well beyond the levels permitted withconventional processes such as low-pressure casting processes. Becauseof the additional use of prior art swell sequence cooling (DE-PS 26 46060) the improvements referred to are extended in an optimum way.Accordingly, it is proposed to use a process wherein the mould, prior tobeing filled, is provided with an operating temperature and wherein,after the mould has been filled, cooling takes place in a graduated wayin terms of time from the end zones to the feeder zones until thesolidification process is complete.

Improvements can also be achieved in respect of the consumption ofprotective gas because by using a protective gas pump, it is not onlypossible to apply several bar of pressure, but also to recover theprotective gas during the subsequent process of lowering the pressure.In this way, any losses are limited to unavoidable leakages.

When using alloys which, in the molten condition, react less strongly togases of the atmosphere, it is possible to do without protective gaswhich, as a rule, is expensive and, instead, to increase the pressure byintroducing compressed air, with all the remaining advantages beingmaintained.

Finally, the processes as proposed are ideal for being carried out in acasting cell sealed against the environment with the objective ofeliminating foundry emissions.

For this purpose, it is particularly advantageous to use a combinedmelting and metering furnace according to DE-PS 20 41 588, which at thesame time solves the problem of introducing material charges. A meltingfurnace is provided with a gas-proof charging chamber with a chargingmember which conveys a quantified amount of melt into the casting ormelt container.

Preferred embodiments of the process are characterized in that theexcess pressure in the interior of the casting container is reduced bycompressed air.

Another preferred embodiment of the process accordingly is characterizedin that the longitudinal axis of the mould cavity for an oblongcomponent extends in the direction of the rotational axis. Also,according to the process a mould cavity is provided with cores extendingas far as a component surface is aligned, together with the cores so asto point towards the cross-sectional face of the ingate.

A preferred embodiment of the process for producing a cylinder head ofan internal combustion engine with an upper and forming camshaft bearingblocks and a lower and forming combustion chamber faces is characterizedin that the mould cavity is arranged in such a way that the upper end ofthe cylinder head is aligned so as to point towards the cross-sectionalface of the ingate.

A preferred process for producing a cylinder crank housing of aninternal combustion engine with an upper end receiving a cylinder headand a lower end forming crankshaft bearing blocks is characterized inthat the mould cavity is arranged in such a way that the lower end ofthe cylinder crank housing is aligned so as to point towards thecross-sectional face of the ingate.

A preferred process for producing a cylinder crank housing of aninternal combustion engine with an upper end receiving a cylinder headand a lower end forming crankshaft bearing blocks is characterized inthat the mould cavity is arranged in such a way that the upper end ofthe cylinder crank housing is aligned so as to point towards thecross-sectional face of the ingate.

Further preferred embodiments of the process are characterized in thatthe position of the ingate is adapted to the geometry of the mouldcavity in such a way that the melt moves in a turbulence-free wayunderneath the closed bath surface, in accordance with the principle ofcommunicating tubes, from the casting container into the mould cavity;or in that the casting container is connected to the mould cavity notonly by the ingate but also by at least one further over-flow channel;or in that the further over-flow channel extends substantially along thecomponent length, parallel to the ingate.

Preferred embodiments of the process further are characterized in thatthe ingate and optionally the further overflow channel form the endfaces of the outer component walls; that during the mould fillingoperation or during the solidification process, the pressure in theinterior of the casting container is increased up to 100 bar; that forthe purpose of evacuating the air, the pressure in the interior of thecasting container is reduced down to 0.005 bar; or in that aftercompletion of the filling operation, the thermal conditions in the mouldare controlled by cooling processes graduated in terms of time andspace.

In a preferred embodiment of the device there are provided sealing meansfor sealing the casting container in a gas-proof way, and pressureincreasing means for increasing the internal pressure in the castingcontainer.

A preferred embodiment of the device is characterized in that thepressure increasing means form part of the protective gas pumping andstoring system; or is characterized in that the protective gas pumpingand storing system comprises means for returning the protective gas fromthe casting container into a protective gas store; or is characterizedby a metering device, especially a metering furnace for filling thecasting container with a quantity of melt for one casting operation; oris characterized by a cooling device for the mould; or is characterizedin that the protective gas supply means between the metering furnace andthe casting container are formed by a resilient gas-proof couplingespecially a convoluted boot; or is characterized in that the gas-proofseal at the casting container is provided in the form of a slide whichis positioned in such a way that during the mould filling operation itis not subjected to the pressure of melt.

Other preferred embodiments of the device are characterized in that thecasting container is connected to the mould not only by the ingate, butalso by at least one further over-flow channel; or in that the furtherover-flow channel substantially extends along the component length,parallel to the ingate; or in that the width of the ingate issubstantially constant and small relative to its length.

Further preferred embodiments of said device are characterized in thatthe casting container is provided with a heating system; optionally inthat the casting container together with a mould is rotatable around alongitudinal axis positioned in a cross-sectional plane of the ingate;or finally in that the entire melting and casting system consisting of amelting and metering furnace, a rotatable casting device with a castingcontainer, and a mould and manipulators for inserting the cores andremoving the components is arranged in a closed casting cell.

Advantageous embodiments of the process and device are defined in thesub-claims to whose contents reference is hereby made.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, the invention will be described with the help of embodiments anddrawings wherein

FIG. 1 is a vertical section through a casting container with a mouldalong the sectional line A-B according to FIG. 2.

FIG. 2 is a vertical section through a casting container with a mouldaccording to FIG. 1, extending perpendicularly relative to therotational axis.

FIG. 3 is a systematic illustration of a casting cell having theequipment suitable for carrying cut the processes in accordance with theinvention.

FIG. 4 is a vertical section through a casting container with a mouldthrough the rotational axis in a second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the embodiment according to FIG. 1, a mould 31 with a mould cavity 1is formed by a mould cover plate 2, side part 3, cores 4 and a mouldbase plate 5. Below the mould base plate 5 there is positioned a castingcontainer 30 with a housing 6 and a refractory lining 7, which container30 contains a quantity of melt 8 metered so as to be sufficient for onecasting operation. The quantity of melt 8 is introduced, especiallyunder protective gas, by means of a metering furnace (not illustrated)through the filling aperture 9, with the seal being in the opencondition. Subsequently, the seal 10 is closed. The seal 10 is shown tohave a connection 11 for protective gas. Furthermore, the Figure showsthe horizontal rotational axis 12 of the casting device, which extendsin the longitudinal direction of the mould 31 and casting container 30.The aperture in the mould base plate 5 is formed by an ingate 13 with alarge cross-section.

In arrow above the mould cover plate 2 symbolises the direction ofmovement of same for removing the finished component from the mould.

FIG. 2 again shows the mould 31 with the mould cavity 1, consisting ofthe mould cover plate 2, side parts 3, cores 4 and the mould base plate5. The ingate 13 and a communication therefore channel 14 extendingparallel thereto are identifiable in the base plate 5. The castingcontainer 30 can be seen to comprise the housing 6, the refractorylining 7 and contains the quantity of melt 8 metered so as to besufficient for one casting operation.

By rotating the entire casting equipment anti-clockwise around therotational axis 12, the melt flows through the ingate 13 With a largecross-section in a quiet, turbulence-free way into the mould cavity 1and completely fills same within a few seconds. At the end of therotational movement, the casting container 30 is positioned above themould base plate 5. Now, by means of the pressure connection 11, theinternal pressure, especially the protective gas pressure, is increasedabove the melt which solidifies in the mould cavity 1 and whose totalvolume also comprises the necessary feeder volume, as a result of whichdense feeding conditions for the casting are ensured. After completionof the solidification process, the excess pressure may be reduced tonormal pressure, the mould may be opened, and the sufficiently cooledcasting may be removed, whereupon a new casting cycle begins.

Arrows at the side of the mould side parts 3 symbolise the direction ofmovement thereof for the purpose of removing the casting from the mould.

FIG. 3 shows, inside a casting cell 21, a rotatable casting device 19with a rotary drive 27 as well as a casting container 30 and a mould 31with connecting means 32 connecting same. The rotational axis 12 of thecasting device is also shown. By means of a pipeline 26, the castingcontainer 30 is connected to a pumping and storage system 18, 28illustrated symbolically only. Within the casting cell 21, there isarranged a metering furnace 15 which, by means of a resilient gas-proofcoupling 23, is connected to the filling aperture 9 of the castingcontainer 30. By means of a sluice 22, the metering furnace 15 isconnected to a region outside the casting cell 21. The sluice 22 mayalternatively be connected to a charging device 16 for lumpy material orto a charging device 17 for liquid material. The casting cell comprisesa further sluice 22. Above the mould 31 there is shown a manipulator 20for the cores.

FIG. 4 shows a casting device consisting of a casting container 30 and amould 31.

The casting container 30 differs from that shown in FIG. 1 in that itdoes not comprise a filling aperture. However, within the refractorylining 7 it comprises heating means 24. A solid quantity of metal 25 hasbeen inserted into the casting container 30. In its cross-sectionextending perpendicularly relative to the rotational axis 12, saidcasting device corresponds to that shown in FIG. 2.

The mould 31 substantially corresponds to that shown in FIG. 1. Itcomprises a mould cover plate 2, mould side parts 3 and a mould baseplate 5. However, the side parts are shown to comprise cooling means 29.Cores 4 are inserted into the mould. The rotational axis of the devicehas been given the reference number 12.

We claim:
 1. A process for casting components from metal alloy, byrotating an apparatus comprising a mould (31) and casting container(30);said mould having a mould cavity (1) and said casting containerhaving an interior for containing a melt, said mould and castingcontainer held in fixed relationship to one another, wherein saidcontainer is located below said mould prior to rotating; said apparatusfurther comprising at least one ingate (13) which extends substantiallyfrom one end of the mould to an opposite end of said mould in ahorizontal direction along an axis of rotation, said ingate providing anopen connection between said mould cavity (1) of said mould (31) and theinterior of the casting container; said apparatus also comprising atleast one communication channel (14), which provides an additional openconnection between the mould cavity (1) and the casting container (30);the casting process comprising: rotating the apparatus so that thecasting container (30) is located below the mould (31); filling thecasting container (30) with sufficient melt for a single casting, withboth the at least one ingate and the at least one communication channelbeing free of melt prior to rotating; sealing said casting container soas to be gas-proof; rotating the apparatus around a horizontal axis (12)in such a way that the melt is conveyed into the mould (31), with theflow of melt being effected through the at least one ingate and with aflow of gases being effected through the at least one communicationchannel (14) at a beginning of said rotating step; further rotating saidapparatus until said casting container (30) is positioned above saidmould (30) and said mould cavity (1), said at least one ingate and saidat least one communication channel are filled with melt, wherein said atleast one ingate and communication channel act as raisers; pressurizingthe interior of the casting container at least temporarily during themould filling and solidification process.
 2. A process for castingcomponents from metal alloy, by rotating an apparatus comprising a mould(31) and casting container (30);said mould having a mould cavity (1) andsaid casting container having an interior for containing a melt, saidmould and casting container held in fixed relationship to one another,wherein said container is located below said mould prior to rotating;said apparatus further comprising at least one ingate (13) which extendssubstantially from one end of the mould to an opposite end of said mouldin a horizontal direction along an axis of rotation, said ingateproviding an open connection between said mould cavity (1) of said mould(31) and the interior of the casting container; said apparatus alsocomprising at least one communication channel (14), which provides anadditional open connection between the mould cavity (1) and the castingcontainer (30); the casting process comprising: rotating the apparatusso that the casting container (30) is located below the mould (31);filling the casting container (30) with sufficient melt for a singlecasting, with both the at least one ingate and the at least onecommunication channel being free of melt prior to rotating; sealing saidcasting container; rotating the apparatus around a horizontal axis (12)in such a way that the melt is conveyed into the mould (31), with theflow of melt being effected through the at least one ingate and with aflow of gases being effected through the at least one communicationchannel (14) at a beginning of said rotating step; further rotating saidapparatus until said casting container (30) is positioned above saidmould (30) and said mould cavity (1), said at least one ingate and saidat least one communication channel are filled with melt, wherein said atleast one ingate and communication channel act as raisers; and wherein afeeding volume of the melt remains in the ingate (13) and thecommunication channel (14).
 3. A process according to claim 1 whereinthe casting container (30) is filled with a quantified amount of metal(25) in a solid form for one casting operation and sealed so as to begas-proof, and melting the metal.
 4. A process according to claim 2wherein the casting container (30) is filled with a quantified amount ofmetal (25) in a solid form for one casting operation and tightly sealed,and melting the quantity of melt for one casting operation.
 5. A processaccording to claim 1 or 2, wherein the casting container (30) for themelt is first flushed with protective gas, then filled with saidquantity of liquid melt (8) for one casting operation under protectivegas and finally sealed so as to be gas-proof, and subsequently the meltis conveyed into the mould (31) under protective gas.
 6. A processaccording to claim 5 wherein at least temporarily during the mouldfilling operation and the solidification process, the pressure of theprotective gas in the interior of the casting container (30) isincreased.
 7. A process according to claim 5 wherein after completion ofthe mould filling operation or the solidification process, theprotective gas used is recovered for re-utilization during the pressurerelieving process.
 8. A process according to claim 5 wherein the air islargely evacuated from the casting container (30) before it is flushedwith protective gas.
 9. A process according to claim 3 or 4, wherein thecasting container (30) for the melt after being sealed so as to begas-proof, then is flushed with protective gas and the mount of metal(25) is melted for the quantity of melt for one casting operation andsubsequently the melt is conveyed into the mould (31) under protectivegas.
 10. A process according claim 2 or 4, wherein part of the meltremains in the entire cross-section of the casting container (30) in theform of a feeding volume.
 11. A process according to claim 2 or 4,wherein at least temporarily during the mould filling operation and thesolidification process, the pressure in the interior of the castingcontainer (30) is increased.
 12. A process according to one of claims 1,8, 2 and 4, wherein the longitudinal axis of the mould cavity (1) for anoblong component extends in the direction of the rotational axis (12).13. A process according to one of claims 1, 3, 2 and 4, wherein a mouldcavity (1) is provided with cores (4) extending as far as thecross-section of the ingate.
 14. A process according to one of claims 1,3, 2 and 4, wherein the position of the ingate (13) is adapted to thegeometry of the mould cavity (1) in such a way that the melt moves in aturbulence-free way underneath the closed bath surface, in accordancewith the principle of communicating tubes, from the casting container(30) into the mould cavity (1).
 15. A process according to one of claims1, 3, 2 and 4, wherein the at least one communication channel (14)extends substantially along the component length, parallel to the ingate(13).
 16. An apparatus comprising a mould (31) and casting container(30);said mould having a mould cavity (1) and said casting containerhaving an interior for containing a melt and having a volume for holdinga quantity of melt for a single casting; a connecting means for holdingsaid mould and casting container in a fixed relationship to one another,and said container is located below said mould prior to rotating; rotarydriving means for rotating the casing container (30) together with themould (31) around a horizontal axis (12); at least one ingate (13) whichextends substantially from one end of the mould to an opposite end ofsaid mould in a horizontal direction along an axis of rotation, saidingate providing an open connection between said mould cavity (1) ofsaid mould (31) and the interior of the casting container; and at leastone communication channel (14), which is distal from the at least oneingate (13) transverse with respect to the direction of the horizontalaxis and provides an additional open connection between the mould cavity(1) and the casting container (30).
 17. A device according to claim 16wherein there are provided sealing means (10) for sealing the castingcontainer in a gas-proof way, and pressure increasing means (18) forincreasing the internal pressure in the casting container.
 18. A deviceaccording to claim 16 or 17 wherein the communication channel (14)substantially extends along the component length, parallel to the ingate(13).
 19. A device according to claim 16 or 17, wherein the width of theingate (13) is substantially constant and small relative to its length.20. A device according to claim 16 or 17, wherein the casting container(30) together with a mould (31) is rotatable around a longitudinal axispositioned in a cross-sectional plane of the ingate (13).